Someone may have solved Doctor Who's oldest plot hole

Of course, in real life this is down to the limitations of making a TV show where former can’t be called back at a moments’ notice (which would also be confusing for most viewers) and time travel isn’t actually a factor – it’d be pretty tricky to get Roger Delgado back as the Master 43 years after his death.

But it’s still one of those niggly little details that has always bothered fans – at least until one enterprising Whovian came up with a brilliant in-universe explanation.

In SteamDelta’s post, he suggests that the reason we only see the Time Lords (and Time Lord planet Gallifrey itself, including its Time War years) in order is simple – it's because of the way that Tardises work.

As he explains, it’s all really down to the Eye of Harmony:

We have to say, this is extremely clever. While we might have imagined Tardises could have some sort of built-in system that stops them getting out of sync with each other or Gallifrey, this extra leap – suggesting that the laws of time and paradoxes mean it’s physically impossible for Eye of Harmony energy to exist in non-chronological order – is a mental leap of pure genius.

But we know what you’re thinking. “What about all the times when multiple Doctors met each other?” we hear you scoff. “Surely their Tardises would be out of sync in that case?”

Luckily, the theory has an answer to that too…

Sure, 2013 anniversary special The Day of the Doctor did see multiple incarnations meet by using their Tardises, but by that point Gallifrey was gone and the modern Doctor’s Tardises weren’t being fuelled by the Eye of Harmony. As demonstrated in 2005 and 2007 episodes, the Doctor now charges the Tardis directly from the Time Vortex using temporal rifts (like the one in Cardiff guarded by Torchwood), so in the revived series the “chronological lock” (we’re calling it that because it sounds cool) imposed by the Eye of Harmony wouldn’t apply. Ipso facto, different Time Lords could have met in any order – except that there weren’t any left to do so.

Now of course there are a few more Time Lords about after the return of Gallifrey in 2015 episode Hell Bent, so it seems reasonable to assume that the rule is back in effect and obsessive Whovians can breathe a sigh of relief that it all makes sense again. Phwho!

Then again, with that said can somebody please get working on a way that a multi-Master TV storyline could still come about? The world needs this, no matter what the cost to space and time.

Doctor Who will return to BBC1 this Christmas, and for a full series in April 2017